1. Field of the Invention
This invention relates to high magnification range compact zoom lenses.
2. Description of the Prior Art
High range zoom lens proposed in Japanese Laid-Open Patent Applications Nos. SHO 57-161804 (published Oct. 3, 1982) and SHO 57-192917 (published November 27, 1982) are constructed with four lens groups all of which move at different speeds during zooming and have the advantage of extending the varifocal range. In particular, imparting a dependent movement into the frontmost or first lens group assists in promoting the magnification varying effect of the second lens group. A zoom lens having a high range but minimum bulk and size is thus achieved. In the zoom lens of Japanese Laid-Open Patent Application No. SHO 57-161804, however, the third lens group is positioned farther away from the image plane and has a weaker refractive power than the fourth lens group. Accordingly, the back-focal distance is unduly long, and, therefore, the entire lens system is long in the longitudinal direction. In Japanese Laid-Open Patent Application No. SHO 57-192917, on the other hand, the refractive powers of the third and fourth lens groups are both too strong to allow for good correction of aberrations with ease.